docs: def ep_style_string(self):
          """Serialize object to an EnerygPlus SizingPeriod:DesignDay.
  
          Returns:
              ep_string: A full string representing a SizingPeriod:DesignDay.
          """
          # Put together the values in the order that they exist in the ddy file
          ep_vals = [self.name,
                     self.sky_condition.month,
                     self.sky_condition.day_of_month,
                     self.day_type,
                     self.dry_bulb_condition.dry_bulb_max,
                     self.dry_bulb_condition.dry_bulb_range,
                     self.dry_bulb_condition.modifier_type,
                     self.dry_bulb_condition.modifier_schedule,
                     self.humidity_condition.hum_type, '',
                     self.humidity_condition.schedule, '', '',
                     self.humidity_condition.wet_bulb_range,
                     self.humidity_condition.barometric_pressure,
                     self.wind_condition.wind_speed,
                     self.wind_condition.wind_direction,
                     self.wind_condition.rain,
                     self.wind_condition.snow_on_ground,
                     self.sky_condition.daylight_savings_indicator,
                     self.sky_condition.solar_model,
                     self.sky_condition.beam_shced,
                     self.sky_condition.diff_sched, '', '', '']
  
          # assign humidity values based on the type of criteria
          if self.humidity_condition.hum_type == 'Wetbulb' or \
                  self.humidity_condition.hum_type == 'Dewpoint':
                      ep_vals[9] = self.humidity_condition.hum_value
          elif self.humidity_condition.hum_type == 'HumidityRatio':
              ep_vals[11] = self.humidity_condition.hum_value
          elif self.humidity_condition.hum_type == 'Enthalpy':
              ep_vals[12] = self.humidity_condition.hum_value
  
          # assign sky condition values based on the solar model
          if self.sky_condition.solar_model == 'ASHRAEClearSky':
              ep_vals[25] = self.sky_condition.clearness
          if self.sky_condition.solar_model == 'ASHRAETau':
              ep_vals[23] = self.sky_condition.tau_b
              ep_vals[24] = self.sky_condition._tau_d
              ep_vals.pop()
  
          # put everything together into one string
          comented_str = ['  {},{}{}\n'.format(
              str(val), ' ' * (60 - len(str(val))), self.comments[i])
                          for i, val in enumerate(ep_vals)]
          comented_str[-1] = comented_str[-1].replace(',', ';')
          comented_str.insert(0, 'SizingPeriod:DesignDay,\n')
          comented_str.append('\n')
  
          return ''.join(comented_str)